Adjustment fitting

ABSTRACT

Adjustment fitting, in particular for a motor vehicle seat, having a first fitting part and having a second fitting part that is rotationally adjustable relative to the first fitting part about an axis of rotation, wherein the first fitting part has associated with it an outer wheel with internal teeth, in which wheel is inserted, in the manner of a wobble mechanism, an inner wheel with external teeth hat is associated with the second fitting part, and wherein the inner wheel forms a receiving space that is eccentric to the axis of rotation, and having an eccentric cam rotatably inserted in the eccentric receiving space, having a drive shaft for driving the eccentric cam. A central seal is placed in an axial gap between the two fitting parts.

This nonprovisional application is a continuation of U.S. applicationSer. No. 12/966,922, which was filed on Dec. 13, 2010 now U.S. Pat. No.8,444,521, and which is a continuation of International Application No.PCT/EP2009/004087, which was filed on Jun. 6, 2009, and which claimspriority to German Patent Application No. DE 10 2008 028 096.8, whichwas filed in Germany on Jun. 13, 2008, and which are all hereinincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns an adjustment fitting, in particular for a motorvehicle seat, having a first fitting part and a second fitting part thatis rotationally adjustable relative to the first fitting part about anaxis of rotation, wherein the first fitting part has associated with itan outer wheel with internal teeth, in which wheel is inserted, in themanner of a wobble mechanism, an inner wheel with external teeth that isassociated with the second fitting part, and wherein the inner wheelforms a receiving space that is eccentric to the axis of rotation,having an eccentric cam rotatably inserted in the eccentric receivingspace, and having a drive shaft for driving the eccentric cam.

2. Description of the Background Art

In an adjustment fitting of this nature, the first fitting part and thesecond fitting part are connected in the manner of a wobble mechanism,wherein the inner wheel rolls with its external teeth along the internalteeth of the outer wheel with a wobbling motion when the eccentric camis driven. The number of teeth in the external teeth differs from thenumber of teeth in the internal teeth. One full rotation of theeccentric cam results in a rotation of the inner wheel relative to theouter wheel by the difference in tooth count. An adjustment fitting withwobble mechanism has become established in the automotive industry foradjusting the backrest relative to the seat base of a motor vehicleseat. A wobble mechanism can be implemented with relatively fewmechanical parts, and permits flat construction together with atransmission ratio desirable for adjustment.

An adjustment fitting of the aforementioned type is known from DE 102005 053 312 B3, for example. There, a cap is disclosed that can beclipped to the circumference of a rotary adjustment element by means ofa radially flexible sealing lip, and that seals the receiving spaceagainst a fitting part under axial preloading. The radially flexiblesealing lip is intended to prevent rotation of the cap relative to thefitting part and thus loss of seal. Instead, the cap rotates relative tothe rotary adjustment element.

A cap for the receiving space is also known from DE 101 44 840 B4 for anadjustment fitting of the aforementioned type. In this design, the capis composed of a sealing ring and a cover plate, wherein the outer edgeof the sealing ring seals against a fitting part under axial preloading.The sealing ring there slides on the fitting part when the fitting isactuated.

In addition, an adjustment fitting with a cap of the above-mentionedtype is known from DE 10 2005 056 728 B3. Here, too, the edge of the capcovers the eccentric receiving space under axial preloading.

The prior art caps for covering the eccentric receiving space serve tokeep dirt and other contaminants away from the joint region of theadjustment fitting. In particular, no paint should get into the interiorof the adjustment fitting during painting operations.

This is because an adjustment fitting is typically painted prior to useby a dip painting process, in particular a cathodic dip paintingprocess, in order to achieve improved corrosion resistance. In thisprocess, penetration of paint into the interior of the fitting is to beavoided, since paint that gets inside can undesirably affect themechanical parts that make up the transmission. Under somecircumstances, this may result in impaired functionality of theadjustment fitting.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an adjustmentfitting that exhibits improved sealing of the eccentric receiving space.This object is attained in an embodiment via an adjustment fitting,whereby a central seal is placed in the axial gap between the fittingparts.

This idea originates from the previous practice of providing permanentcaps for sealing the open axial accesses to the interior space and ofusing grease for sealing gaps in the adjustment fitting that likewiseconstitute an access to the receiving space to prevent the entry ofpaint. With this practice, however, it is possible for the interiorspace of the adjustment fitting to be contaminated with cleaning fluidas early as the pretreatment of the adjustment fitting. Grease can thenbe inadvertently washed out during the dip painting itself, so thatpaint can nevertheless enter. Moreover, escaped grease leads to qualityimpairment during the painting process. Furthermore, only“paint-compatible” grease can be used in the fitting, which isassociated with cost disadvantages.

It has now been found that the axial gap between the fitting parts thatis necessary for relative rotation, which perforce constitutes an accessto the eccentric receiving space of the adjustment fitting, is suitablefor permanent sealing. If a central seal is placed in the axial gapbetween the first and second fitting parts, the access to the outerannular space between the inner wheel and the outer wheel is sealed off.Penetration of dirt and, in particular, paint, through the outer annularspace between the inner wheel and the outer wheel during the paintingprocess is thus reliably and permanently prevented, without giving riseto the problems described with respect to sealing by means of grease. Inthis design, the fitting parts slide along the central seal duringadjustment of the fitting. The central seal thus serves both as a staticand a dynamic seal. The invention thus provides a possible way toachieve further sealing of the transmission parts of the adjustmentfitting in order to reliably prevent the entry of dirt and, inparticular, paint, into the receiving space during the painting process.

As to the material for the central seal, basically any elastomer issuitable as long as it is dimensionally stable enough and, inparticular, withstands a cathodic dip painting process. In particular,the material should withstand temperatures of up to approximately 200°C. A suitable plastic or rubber is possible as the material. Preferably,a polyamide is used as the material for the central seal. The centralseal can fill part of the axial gap, or can fill it completely.

As mentioned, type-specific adapters or adapter plates are joined to theouter and/or inner wheel, for example by welding, in particular by laserwelding, for installation of the adjustment fitting on specific vehicleseats. In particular, an adapter plate that is spaced apart from theouter wheel by an axial gap is preferably joined circumferentially tothe inner wheel. Preferably, the central seal is placed in the axial gapbetween the adapter and the outer wheel in this design.

In an advantageous embodiment, the central seal is designed in a diskshape with an outer sealing rim, wherein the outer sealing rim has anessentially Y-shaped cross-section with legs pointing radially outwardand branching axially apart, which legs spread between the first andsecond fitting parts, in particular between the outer wheel and theadapter. As a result of this design, dirt and, in particular, paint, isreliably kept from penetrating into the aforementioned axial gap. Theinterior space of the adjustment fitting is protected.

It is further preferred for the outer wheel to include an outer wallthat is extended in the axial direction beyond the internal teeth andoverlaps the external teeth of the inner wheel with a radially inwardfacing collar, wherein the central seal has an inner axial sealing rimthat is placed in the collar. The extended outer wall and the overlapwith the external teeth of the inner wheel can also take place inparticular by means of a two-piece design of the outer wheel. In thisdesign, the outer wheel is divided at the internal teeth, so that, in asense, a top shell and a bottom shell are produced. The external teethof the inner wheel are then securely supported or guided between the topand bottom shells. Alternatively, the overlap with the extended outerwall can also take place by means of a retaining element which followsthe internal teeth of the inner wheel in the axial direction in theouter wall of the outer wheel, and is attached, in particular welded, tothe outer wall at an appropriate position. This offers the additionalpossibility of adjusting the axial clearance between the inner and outerwheels.

The inner axial sealing rim of the central seal is then placed in theouter wall of the outer wheel. In this way, rotation and slippage of thecentral seal relative to the outer wheel is prevented. Assembly is alsosimplified in this way.

In a useful manner, the inner axial sealing rim of the central sealterminates in an end that is curved radially inward. In this way theregion of the teeth is additionally protected from welding spatter.

A cap can be provided for sealing the open receiving space.

In an embodiment, the drive shaft can be designed as a continuousbearing journal. This facilitates assembly of the adjustment fitting.Such a bearing journal also offers the ability to hold the components ofthe adjustment fitting together in the axial direction.

The cap and the bearing journal can be designed as a single piece. Ascompared to known caps from the prior art, this design eliminates theneed to attach the cap to an adjusting element, in particular throughthe use of clips or latches. Such a one-piece design is now madepossible because the sealing of the receiving space takes place in theradial direction. Moreover, the one-piece design reduces manufacturingcosts. The assembly of the adjustment fitting is simplified, as well.

In another embodiment of the adjustment fitting, the outer wheelincludes a floor with a central bore, in which the end of the bearingjournal facing away from the cap is mounted, wherein the bearing journalis held against the floor by a locking disk, and wherein the lockingdisk includes a sealing rim that covers the radial gap between thebearing journal and the floor under preloading directed axially towardthe floor. The locking disk thus acts as a cover for the “back” of theadjustment fitting, since it covers the rear, radial gap between thebearing journal and the floor of the outer wheel. Since the locking diskholds the adjustment fitting, it is advantageous for the locking disk tobe mechanically supported by a reinforcing element, in particular anembedded steel element. Once again, the sealing rim of the locking diskcan be made of a suitable elastomer.

The floor on the sides facing the locking disk is recessed in a saucershape. For one, this reduces the axial height of the adjustment fitting.Secondly, it ensures secure rear sealing of the receiving space.

For stable mounting, the floor includes an elongated collar surroundingthe bore, in which collar the bearing journal is mounted. The mountingof the bearing journal is stabilized through the support surface of theelongated collar, which is enlarged in the axial direction. Inparticular, tilting of the bearing journal is reliably prevented in thisway.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWING

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingwhich is given by way of illustration only, and thus, is not limitive ofthe present invention, and wherein the sole FIGURE illustrates anexample embodiment, showing a cross-sectional view of an adjustmentfitting with sealing of the eccentric receiving space.

DETAILED DESCRIPTION

An example embodiment of the invention is described in detail withreference to the drawing. The only FIGURE, FIG. 1, shows across-sectional view of an adjustment fitting with sealing of theeccentric receiving space.

Visible in the cross-sectional depiction in FIG. 1 is an adjustmentfitting 1, which includes a first fitting part 2 and a second fittingpart 3, which are rotationally adjustable relative to one another aboutan axis of rotation. The first fitting part 2 has an outer wheel 4, towhich is attached, in particular by welding, a suitable backrest adapter6 for later installation on a seat backrest. The second fitting part 3includes an inner wheel 7 and a seat adapter 8 connected thereto forattachment to a seat base.

The outer wheel 4 is designed as a ring gear with a floor 9 and an outerwall 10, wherein internal teeth 12 are provided on the outer wall 10.The outer wheel 4 is divided along the internal teeth 12, and iscomposed of a first shell 13 and a second shell 14. A circumferentialcollar 15 of the second shell 14 engages around the external teeth 17provided on a raised inner wall 16 of the inner wheel 7. In this way,the inner wheel 7 is securely held axially between the first shell 13and the second shell 14 of the outer wheel 4. In addition, the outerwheel 4 has a separately inserted dome 20, which bears a circumferentialelongated collar 21. The design of a separate dome 20 offers thepossibility of optimizing the different tribological properties withregard to mounting and transmission through appropriate selection ofmaterials.

Formed between the elongated collar 21 and the raised inner wall 16 ofthe inner wheel 7 is an eccentric, annular receiving space 24 in which afirst eccentric cam part 26 and a second eccentric cam part 27 areplaced for driving the inner wheel 7. Under rotation, the two eccentriccam parts 26, 27 form a variable overall eccentricity and are preloadedby means of a spring element 30 to produce a maximum overalleccentricity. In this preloaded starting position, the external teeth 17of the inner wheel 7 are pressed against the internal teeth 12 of theouter wheel 4 without play in the direction of maximum eccentricity, sothat runout of the fitting parts 2, 3 relative to one another is notpossible.

For actuating the eccentric cam parts 26, 27, a carrier plate 31 inwhich the carrier projections 33 of the respective eccentric cam parts26, 27 engage, is also placed in the eccentric receiving space 24. Thecarrier plate 31 is attached in a rotationally fixed manner to thecentral drive shaft 34, which in the present case is designed as acontinuous bearing journal 35. When the bearing journal 35 is driven orrotated, the eccentric cam parts 26, 27 are rotated against thepreloading of the spring element 30 via the carrier plate 31 attached ina rotationally fixed manner, so that the inner wheel 7 now rests againstthe outer wheel 4 with play. The overall eccentric cam composed of theeccentric cam parts 26, 27 can be rotated, with the external teeth 17 ofthe inner wheel 7 rolling on the internal teeth 12 of the outer wheel 4.One full rotation of the eccentric cam results in a rotation of theinner wheel 7 relative to the outer wheel 4 corresponding to adifference in tooth count between the external teeth 17 and the internalteeth 12.

In order to drive the bearing journal 35, the journal has a squareopening 36 on its top side. Provided on the opposite side is areceptacle for a further shaft which is provided for driving acorresponding adjustment fitting on the other side of the vehicle seatif desired.

To reduce the friction between the eccentric cam parts 26, 27 and theinner wheel 7, a plain bushing 37 is placed in the inner circumferenceof the inner wheel 7.

The bearing journal 35 is designed as a single piece with a cap 38,which seals the eccentric receiving space 24 with respect to theoutside. The cap 38 is designed in the shape of a disk and is offsetradially with respect to the drive shaft 34. In other words, the cap 38is eccentric in design. The eccentric cap 38 additionally includes asealing rim 40 that is drawn axially downward, which projects inside theeccentric receiving space 24. By means of preloading directed radiallyoutward toward the inner wall 16 of the inner wheel 7, thecircumferential sealing rim 40 seals the eccentric receiving space 24with respect to the outside. The sealing rim 40 is made of a moldableelastomer, and is molded onto the bearing journal 35 by means of atwo-component injection molding process. It can be seen that the axiallength of the sealing rim 40 is dimensioned such that different variantsof the adjustment fitting 1, which differ in axial height, can be sealedwith one and the same bearing journal 35. An axial offset of the sealingrim 40 with respect to the inner wall 16 within a certain limit does notchange the sealing function. In particular, this also applies to thecase where the axial sealing wall 40 does not seal against the innerwall 16 of the inner wheel 7, but rather directly against acircumferential rim of the seat adapter 8.

On the side facing away from the cap 38, the bearing journal 35 is heldon the adjustment fitting 1 by means of a locking disk 43. The fittingparts 2, 3 are axially held together by the outer wheel 4 implemented asa ring gear. The locking disk 43 has a circumferential sealing rim 44,and is held in a saucer-shaped recess 47 of the floor 9 or of theseparate dome 20. Axial preloading of the sealing rim 44 with respect tothe floor 9 is achieved by means of a clip attachment of the lockingdisk 43 to the bearing journal 35. As a result, not only does thelocking disk 43 hold the bearing journal 35 in the adjustment fitting 1,it also seals the radial gap between the bearing journal 35 and the dome20. On this side, too, penetration of dirt and, in particular,penetration of paint during the painting process is thus reliablyprevented.

The seat adapter 8, in the form of a seat adapter plate, is attachedcircumferentially, in particular welded, to the inner wall 16 of theinner wheel 7. The backrest adapter 6 is spaced axially away from theouter wheel 4 in order to permit rotation relative to one another. Inaddition, a disk-shaped central seal 50 is placed in the resultant axialgap 48 between the seat adapter 8 and the outer wheel 4. In this way,the interior of the adjustment fitting 1 is fully sealed with respect tothe outside. Neither dirt nor paint can enter the internal transmissionparts through the outer annular gap between the inner wheel 7 and theouter wheel 4, as well.

The disk-shaped central seal 50 also has an outer sealing rim 52 with anessentially Y-shaped cross-section. Here, the two legs 53, 54 of theouter sealing rim 52 extend radially outward and brace axially againstthe seat adapter 8 and against the outer wheel 4. In this way, dirt and,in particular, paint, is reliably prevented from penetrating theinterior space of the adjustment fitting 1 through the axial gap 48.

In addition, the central seal 50 has an inner axial sealing rim 57 withwhich it is placed in the collar 15 of the outer wheel 4. By this means,rotation of the central seal 50 relative to the outer wheel 4 isprevented. The inner sealing rim 57 has an inwardly curved end 58. Bythis means, the internal transmission of the adjustment fitting 1 isprotected from welding spatter during the manufacturing process.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are to beincluded within the scope of the following claims.

What is claimed is:
 1. An adjustment fitting for a motor vehicle seat,the adjustment fitting comprising: a first fitting part; a secondfitting part that is rotationally adjustable relative to the firstfitting part about an axis of rotation; the first fitting part having anouter wheel, the outer wheel having internal teeth; the second fittingpart having an inner wheel configured to be insertable in the outerwheel in the manner of a wobble mechanism, the inner wheel havingexternal teeth, the inner wheel forming a receiving space that iseccentric to the axis of rotation; an eccentric cam rotatably insertedin the eccentric receiving space; a drive shaft configured to drive theeccentric cam; an adapter joined circumferentially to an outer surfaceof the inner wheel; and a central seal arranged in an axial gap betweenthe adapter and the outer wheel, wherein the outer surface of the innerwheel is parallel to the axis of rotation.
 2. The adjustment fittingaccording to claim 1, wherein a cap is provided for covering the openreceiving space.
 3. The adjustment fitting according to claim 2, whereinthe cap has a sealing rim, a portion of the sealing rim extendingaxially downward in the inner wheel, so as to project inside theeccentric receiving space.
 4. The adjustment fitting according to claim1, wherein the drive shaft is configured as a continuous bearingjournal.
 5. The adjustment fitting according to claim 4, wherein a capis provided for covering the open receiving space, and wherein the capand the bearing journal are configured as a single piece.
 6. Theadjustment fitting according to claim 1, wherein the central seal isconfigured in a disk-shape and overlays at least a portion of the innerwheel and the outer wheel in a radial direction with respect to thedrive shaft.
 7. An adjustment fitting for a motor vehicle seat, theadjustment fitting comprising: a first fitting part; a second fittingpart that is rotationally adjustable relative to the first fitting partabout an axis of rotation; the first fitting part having an outer wheel,the outer wheel having internal teeth; the second fitting part having aninner wheel configured to be insertable in the outer wheel in the mannerof a wobble mechanism, the inner wheel having external teeth, the innerwheel forming a receiving space that is eccentric to the axis ofrotation; an eccentric cam rotatably inserted in the eccentric receivingspace; a drive shaft configured to drive the eccentric cam; an adapterjoined circumferentially to the inner wheel; and a central seal arrangedin an axial gap between the adapter and the outer wheel, and wherein thecentral seal is configured in a disk shape with an outer sealing rim,wherein the outer sealing rim has an essentially Y-shaped cross-sectionwith legs pointing radially outward and branching axially apart, whichlegs spread between the first and second fitting parts.
 8. Theadjustment fitting according to claim 7, wherein one leg of the Y-shapedcross section of the outer sealing rim braces axially against theadapter, and the second leg of the Y-shaped cross section of the outersealing rim braces axially against the outer wheel.
 9. An adjustmentfitting for a motor vehicle seat, the adjustment fitting comprising: afirst fitting part; a second fitting part that is rotationallyadjustable relative to the first fitting part about an axis of rotation;the first fitting part having an outer wheel, the outer wheel havinginternal teeth; the second fitting part having an inner wheel configuredto be insertable in the outer wheel in the manner of a wobble mechanism,the inner wheel having external teeth, the inner wheel forming areceiving space that is eccentric to the axis of rotation; an eccentriccam rotatably inserted in the eccentric receiving space; a drive shaftconfigured to drive the eccentric cam; an adapter joinedcircumferentially to the inner wheel; and a central seal arranged in anaxial gap between the adapter and the outer wheel, and wherein the outerwheel includes an outer wall that is extended in the axial directionbeyond the internal teeth and overlaps the external teeth of the innerwheel with a radially inward facing collar, and wherein the central sealhas an inner axial sealing rim that is placed in the collar.
 10. Theadjustment fitting according to claim 9, wherein the inner axial sealingrim terminates in an end that is curved radially inward.
 11. Anadjustment fitting for a motor vehicle seat, the adjustment fittingcomprising: a first fitting part; a second fitting part that isrotationally adjustable relative to the first fitting part about an axisof rotation; an outer wheel associated with the first fitting part, theouter wheel having internal teeth; an inner wheel configured to beinsertable in the outer wheel in the manner of a wobble mechanism, theinner wheel having external teeth that are associated with the secondfitting part, the inner wheel forming a receiving space that iseccentric to the axis of rotation; an eccentric cam rotatably insertedin the eccentric receiving space; a drive shaft configured to drive theeccentric cam; and a central seal arranged in an axial gap between thefirst fitting part and the second fitting part, wherein the drive shaftis configured as a continuous bearing journal, wherein a cap is providedfor covering the open receiving space, and wherein the outer wheelincludes a floor with a central bore, in which an end of the bearingjournal facing away from the cap is mounted, wherein the bearing journalis held against the floor by a locking disk, and wherein the lockingdisk includes a sealing rim that covers a radial gap between the bearingjournal and the floor under preloading directed axially toward thefloor.
 12. The adjustment fitting according to claim 11, wherein thefloor on a side facing the locking disk is recessed in a saucer shape.13. The adjustment fitting according to claim 11, wherein the floorincludes an elongated collar surrounding the bore, and wherein thebearing journal is mounted in the collar.